May 19 – All The Way Down

Today’s factismal: Galápagos tortoises are an example of island dwarfism.

Quick! What weighs 550 lbs, is big enough to ride on, and is the smallest of its kind? Why, it is the Galápagos Island tortoise. These huge reptiles are amazing animals. They move at a top speed of nearly two miles a day and feed of a wide variety of vegetables (such as cacti and berries) and small animals (such as lizards and fish). Young tortoises will eat more than 1/8th of their body weight each day, turning the excess into fat that they store for food during the lean months. And those lean months can be long, indeed; the Galápagos tortoise can live for a year on the food and water stored in its shell as fat.

A Galápagos tortoise looking for lunch (My camera)

A Galapagos tortoise looking for lunch
(My camera)

But amazing as that is, what is even more amazing is that the Galápagos tortoise is probably the last of its lineage of giant tortoises, all of which were larger than it. Consider the Hesperotestudo crassiscutata, a giant gopher tortoise, which was about twice as big as the Galápagos tortoise and lived in Texas and Central North America until about 12,000 years ago. And then there was Megalochelys atlas; it lived in India and was another tortoise that makes the Galápagos tortoise look like a runt. Let’s not forget the Ninjemys oweni, a spike-covered super tortoise. And if we go back a few million years, there is the great-granddaddy of scary big tortoises, Carbonemys cofrinii. This guy was roughly the size of a Prius and lived on a diet of crocodiles, fish, and molluscs.

This tortoise is looking for lunch in all the wrong places (My camera)

This tortoise is looking for lunch in all the wrong places
(My camera)

Giant tortoises had a survival advantage in a wet world like the Pleistocene. They could jump into the water and survive long ocean voyages until they came to a landing place. Much like a reptilian coconut, they would have used the sea currents to populate islands and new territories. But like the vegetable coconuts, they were too tasty to survive. Other critters would have found them an easy food source. As a result, the mainland tortoises died out as smilodons, cave bears, and hominids munched them into extinction; in the end, only the species that had moved to islands survived.

And those species, including our friend the Galápagos tortoise, suffered the same fate as elephants, hippopotamuses, and even hominids on islands. Each succeeding generation is smaller because the island’s limited resources give a smaller size a survival advantage. In 1964, a biologist came up with the rule that animals that colonize islands tend to either grow larger or smaller to match the resources available on the island. Known as Foster’s Rule, this was a triumph of evolutionary biology. And today we continue to learn about evolution with the help of citizen scientists. One project is the Evolution MegaLab. By counting the number of bands on snail shells, we can see how their predators (thrushes) are forcing snails to change and adapt. To learn more, crawl over to:

March 17 – Thigmowhatsis?

These elephant seals are in the grip of thigmotaxis (My camera)

These elephant seals are in the grip of thigmotaxis
(My camera)

Thigmotaxis is biology-speak for “squeezing into a hug”. It is seen in lots of animals from humans down to baby caterpillars and has lots of causes. Mice do thigmotaxis because it helps them stay close to walls and other solid objects which keeps them safe from predators and brooms. Fish do thigmotaxis because it helps them bunch up and look larger which discourages predators. And elephant seals do thigmotaxis because it helps them get through the stressful molting period.

May 16 – All Mixed Up

Descartes once famously declared “I think therefore I am” (actually, he wrote “cogito ergo sum”, but it works out to the same thing). His thought was that if we can’t trust our senses, we are truly lost. Today, Mary and Peter discover exactly how far they can trust their senses as they explore the world of psychology in the Secret Science Society!


Mary was more than a little annoyed with Peter. They’d made plans to go down to the creek and search for dragonflies as part of his merit badge requirements (she was much better at spotting them than he was), but he was more than half an hour late. Since she was waiting in the clubhouse, normally she wouldn’t have minded; there was plenty to keep her interested while she waited. But the late afternoon heat was making the clubhouse less a place to discover the secrets of the universe and more a place to torture your worst enemy. Finally, she decide to go over to Peter’s house and see what the delay was.

Given that the clubhouse was in Peter’s garage, it didn’t take her long to get to his backdoor. Knocking on it, she called out “Peter! Where are you?”

“Come in!” came Peter’s reply, muffled somewhat by the door.

As Mary stepping in, she suddenly shivered.

“Brr!” Mary exclaimed, he annoyance with Peter’s tardiness momentarily forgotten. “Do you have a parka or something? It’s freezing in here!”

“What do you mean?” Peter asked. “It’s 80 degrees! I keep trying to push the thermostat down, but Mom won’t let me,” he added.

“I don’t wonder,” Mary replied. “It is like an ice cave in here.”

“That’s weird,” said Peter. “It feels warm to me. How can the same temperature feel so different to two people?”

“I dunno – maybe there’s a physics explanation for it? Let’s ask you Mom. Is she doing any experiments right now?”

Peter’s mother, who was an expert astrophysicist, was always willing to explain things to Peter and Mary but if she was working on an experiment, she might forget to use words and just absentmindedly write an equation on the whiteboard in her study.

“No, she’s just balancing the checkbook; we’d be doing her a favor to ask a science question!”

Quickly, the two went into the study where, sure enough, Peter’s mother sat in front of a pile of bills, matching the checks to the bank statement on the screen in front of her. As Peter and Mary entered the room, she turned with a bright smile.

“I thought you two would be out chasing the wild dragonfly,” she said.

“We were supposed to but Peter never showed up,” Mary said. “But we’ve got something else to ask. How come I feel cold and Peter feels hot when we’re in the same room?”

“Peter, you know better than to make another scientist wait,” his mother chided. “You owe Mary an apology -”

“Sorry,” Peter said.

“As for your question, that’s a good one. Would you believe that psychologists are still arguing over it?” As the two shook their heads, she added “maybe we can do an experiment to show part of why it happens.”

At that, the two brightened up. Since they both wanted to be scientists some day, one of their favorite things to do was to perform experiments. Peter’s mother smiled at the sudden interest on their faces.

“OK, let’s go into the kitchen.”

Leading the two young scientists into the kitchen, Peter’s mother took out three large bowls. She then took the bowls to the sink where she filled one with warm water, one with cold water to which she added a couple of ice cubes, and then filled the third with some water from each of the other two bowls.Finally, she placed the bowls on the kitchen table within easy reach of the scientists.

Turning back to Mary and Peter, she said, “you’ve seen my fill the bowls. When I say go, you’ll put one hand into the bowl of warm water and one hand into the bowl of cold water. You’ll leave your hands in there for a minute or so, and then you’ll put both hands into the middle bowl. What do you think you will feel?”

Mary said “Both hands will be in the same water, so they should feel the same thing; it will be lukewarm.”

“I’m not so sure,” Peter said. “You and I are in the same room and we feel different temperatures.”

“Well, there’s only one way to find out,” Peter’s mother said. “Put your hands in the outer bowls now!”

What do you think will happen? Try the experiment!






Peter and Mary put their hands into the two bowls. As they waited for Peter’s mother to give the signals to switch, Peter said “My left hand is cold and my right hand is warm. This isn’t much of an experiment.”

“Wait for it,” his mother replied. “Patience is the hallmark of a good researcher. In five, four, three, two one, NOW move both your hands into the center bowl!”

Quickly the two put their hands into the center bowl and got the shock of their lives. The hand that had been n the warm water felt cold, but the hand that had been in the cold water felt warm.

“Wow! This is weird!” Mary exclaimed. “What is going on?”

“This has to do with how your body senses temperature. You see, we don’t have little thermometers in our skin telling us what the absolute temperature is. Instead, we’ve got sensors that tell us what the change in temperature is. When the temperature is constant, then your sensors don’t notice any change and everything just feels ‘normal’. But if you go from a hot place to a cold one, then they feel the change and tell you that it has gotten colder. And if you go from a cold place to a hot one, then they tell you that the relative temperature has changed and you feel hotter.”

“So that’s why a swimming pool feels cold at first and then you get used to it!” Mary said.

“That’s right,” Peter’s mother replied. “And it is why you can go outside and it will feel hotter than blazes for a bit but before long you are used to it.”

“Cripes!” Peter said. “Outside! Let’s go find those dragonflies!”

“OK,” Mary said,” but then you owe me a cold soda for making me wait so long!”


And with that, the two young scientists ran outside, eager to do more experiments.

May 13 – Silly String

Today’s factismal: The newest medical test uses a piece of string.

If there is one thing that is surer in this world than death or taxes, it is the ingenuity of medical researchers in coming up with new tests to help us live longer, better lives. The tests can be as sophisticated as personalized DNA sequencing or as simple as measuring yourself with a piece of string. But no matter how simple or how complicated the test, the end result is information that can lead to better health.

Since DNA tests are pretty complicated, let’s look at how that piece of string is used and what the test means. To start with, find a long piece of string  and drop it down from the top of your head to the floor. Mark it and cut it so that you  have string that is as long as you are tall. Now match the two ends of the string with each other and stretch the string out into a pair of strings that are half as long as the original one. Now, wrap the doubled string around your middle so that it passes over your belly button. Do the ends meet? Or is there a gap?


If the ends meet, then you pass the test. But if they don’t then you should probably start thinking about what you eat and how much you exercise because you just failed the string test. This test is a variant on the more familiar Body Mass Index (BMI) test that has been used for decades to help doctors pinpoint patients who need to work on their weight. As with the BMI, people who fail this test are at a higher risk of developing problems such as diabetes, heart disease, and gallstones. However, unlike the BMI (which provides a general measure of fit or fat), the string test tells doctors specifically if the extra weight you’ve got is carried around your middle (dangerous) or elsewhere (not so dangerous). Interestingly, in a recent study of the test about one third of the people who passed the BMI failed the BMI indicating that they had an unhealthy fat distribution even though they were near their “ideal weight”.

So the next time you go to your doctor, don’t be surprised if she brings out a piece of string!

May 11 – Say What?

Today’s factismal: The word krak means “there’s a leopard here” in the language of Campbell’s monkeys.

Just a few decades ago, people were convinced that man was the only animal that used language. And then came Karl von Frisch  and the language of the bees. And then came Jane Goodall and the language of the chimpanzees. And then came the language of the orcas, and the language of the crows, and the language of the ants, and pretty soon only the stubbornest biologists were claiming that animals didn’t have a language. But even better was discovering all of those languages was learning what they meant.

A Campbel''s monkey just waiting for the krak of doom (My camera)

A Campbel”s monkey just waiting for the krak of doom
(My camera)

For example, back in 2009, a group of researchers listened to groups of Campbell’s monkeys and slowly pieced together their language. The word krak for example meant “there is a leopard here” while the word boom means “let’s get out of this place” and hok means “Who let that eagle into the jungle?”. (Campbell’s monkey is a very compact language.) Even better, the researchers discovered that the monkeys could use their language much the way that we do by adding suffixes to change the meaning of a word. For example, adding -ful to sorrow makes the new word sorrowful in English. And adding -oo to krak makes the new word krak-oo which means “Something ain’t right here” and adding it to hok makes hok-oo which translates to “The canopy is dangerous right now”.

A warbler singing its heart out (My camera)

A warbler singing its heart out
(My camera)

Those researchers were able to do their work only because the Campbell’s monkey doesn’t move very far. But other researchers are trying to learn the languages of the birds and they do move pretty far. One group is trying to track the Mourning Warbler as it flies from South America to Canada using their songs and they need your help to do it. All you have to do is listen for the songs of the mourning warbler and record them on your smart phone. Email your song files and other information (date, location, number of jellybeans in your pockets)  to the researchers and krak! you’ve done your part tohelp us learn more about how other animals communicate. To learn more, wing on over to:

May 9 – In The Dark

There are two rules in science that every researcher soon learns: what you don’t see is as important as what you do see and a paradox means that you are on the edge of learning something amazing. In today’s adventure, Peter and Mary find this out for themselves as they see what darkness lurks in the hearts of galaxies!


Sharing a sunset with friends is always good. As the sun paints the sky with vivid shades of orange, red, and purple (and a flash of green), you can discuss the important stuff, such as what you like best and where you want to live when you get older. But the best part is just being there with your friends, sharing something unique and special. And that’s what Peter and Mary were doing on a particularly clear summer night – just hanging out and being friends.

Of course, for them, some of the answers were already known. They both liked science best of all, and enjoyed doing experiments whenever they could. And they didn’t really care where they lived as long as it was someplace where they could do experiments, though Mary really preferred Houston simply because that was where all of the other astronauts lived. But there were still some questions that they hadn’t answered. And Mary had one for Peter.

“So why did you mother say we should be out here tonight? She isn’t trying to get you out of the house so she can run more simulations, is she?” Peter’s mother was an astronomer who sometimes needed more peace and quiet than a house with a young son could provide, so she would ask Peter to run errands or do experiments outside while she concentrated.

“No, she just said that it was time that I learned some of the deepest, darkest secrets of the universe and told me to be here after sunset. I wonder what we’ll learn?” he mused.

“You’ll discover that just as soon as we get some basics down,” said a cheerful voice behind them; turning around, they saw Peter’s mother holding three small bags. “Come and grab these binoculars!”

As the two each took a bag and opened it to reveal a good but inexpensive pair of binoculars, Peter’s mother continued her explanation.

“We’re going to look into the night sky and see one of the most amazing things ever described,” she said. “But before we do, we need to figure out how to make sure that we are all looking at the same thing. Any ideas on how we could do that?”

“You keep muttering under your breath about ‘right ascension’ and ‘declination’ when you are working on a problem,” Peter replied.

“But I don’t know what those are!” Mary objected.

“Well, neither do I,” Peter admitted. “But it is what she says.”

“When we are in the lab or using a big, expensive telescope, we do use those terms,” Peter’s mother said. “They are a mathematical grid that helps us locate things in the sky, much as latitude and longitude help on the ground. But we don’t drive around using latitude and longitude. Instead, we use street signs and relative directions like ‘turn left after the next block’.”

“So what are the street signs in the sky?” asked Mary.

“The constellations,” replied Peter’s mother. “They tell us which part of the sky to look in. For example, the nearest star to the Sun is…”

“Alpha Centauri!” Peter interrupted.

“Close but no cigar,” his mother said. “It is actually Proxima Centauri; the name ‘Proxima’ means ‘nearest’ and ‘Centauri’ means that it is found in the Centaurus constellation. But Proxima is too dim to be seen with the naked eye and is right next to Alpha, astronomically speaking, so most non-scientists think that they are the same.”

“Why do we call it Alpha Centauri?” Mary asked.

“Ah, that’s like a street number in our sky map,” Peter’s mother replied. “The stars are given a designation based on their apparent brightness – how bright they look from Earth. The brightest star in a constellation is ‘alpha’, the next-brightest is ‘beta’, then ‘gamma’ and so on. Many of the brightest stars also have a name in Arabic -”

“Like Betelgeuse!” Mary said.

“Right, the good old ‘shoulder of the giant’. And we’ve got ‘the follower’ Aldebaran in Taurus or ‘the tail of the hen’ Deneb in Cygnus. But you can’t drive with a street map in your face and you can’t find stars at night using those names until you’ve got a lot more experience. So tonight, we’ll use the old astronomer standby of ‘face East and make a fist’.”

“Huh?” said Peter. “What good will that do?”

“Well, let’s start by facing East,” his mother replied. Humoring her, the two obediently turned to face the opposite direction from where the Sun had gone down.

“Now spread you hand wide and sweep it from East to directly overhead to West,” she commanded. As they did so, Peter’s mother explained, “What you’ve just done is sweep out half of the ecliptic plane; that’s the band where most of the stuff in the Solar System lives. Most of the planets and asteroids and other junk in our Solar System will be found in the band you just described with your hand. So if we ever go looking for planets, that’s where we can look.”

“Neat!” Mary said. “So we can see Jupiter?”

“If it was up tonight, we could,” Peter’s mother said. “But it won’t be up until well after you two go to bed, which is a shame because you could see the moon of Jupiter with your binoculars. We’ll have to try it some night when Jupiter is up earlier. But for tonight, what I want you to to is face East and count three fists to the North and four fists up. When you put a fist at arm’s length, it is always about ten degrees, no matter who or how old you are, so fists are an astronomer’s favorite quick and dirty measuring method. When you get to the position, look at it and tell me what you see.”

“That’s just old Orion’s sword,” Peter said. “There’s nothing special there.”

“I wouldn’t be so sure,” his mother replied. “Look at it again, only use your binoculars.”

The two looked through their binoculars at the sword hanging from Orion’s belt and let out gasps of wonder.

“It’s full of stars!” Mary exclaimed.

“Even better,” Peter’s mother said. “It is full of baby stars and planets; that is a stellar nursery where new solar systems are being born.”

“Wow!” Peter said. “Is the whole sky like this?”

“That’s exactly why I asked you to come out here tonight,” said his mother. “When I was your age, your grandfather brought me out to a field and showed me what you’ve just seen. And then he made a bet with me. He bet me $10 that I couldn’t find a part of the sky without stars.”

“That’s easy,” Mary said. “There’s an empty patch over there!”

“Look at it through the binoculars,” Peter’s mother said.

“Whoa! It has stars!”

“Yes, that’s right. So here’s my challenge to you two – can you fins any part of the sky that has no stars in it when seen through the binoculars?”

“Sure we can!” Peter said.

“I don’t know,” Mary replied. “I thought my patch was dark but it really wasn’t.”

Well, there is only one way to know for sure,” Peter’s mother said. “Do the experiment!”

What do you think will happen? Do the experiment yourself!







For twenty minutes, Peter and Mary searched the sky looking for patches without stars. Time after time they’d get excited about a seemingly empty area only to see it fill with stars when they looked at it through the binoculars. They tried down near the horizon and up near the zenith overhead, but every area had stars. Finally, the two gave in and admitted that the entire sky was filled with stars.

“No matter where we look, there are stars in the sky,” Peter said. “But why don’t we see them?”

“For the same reason that you don’t see a candle from a mile away,” his mother explained. “Stars are just big light sources in the sky. And the farther away they are, the dimmer they get. You can see them with the binoculars because they gather more light and make dim things visible. Telescopes do the same thing; all binoculars are is two telescopes strapped together. As a matter of fact, when the Hubble telescope stared at one place in the sky for five days, it discovered over a thousand galaxies in a patch of the sky that you could cover with your thumb. That means billions of stars and trillions of planets, all out there in the deepness of space.”

“Wow!” Mary said. “But if there are all of those stars out there, then why is the night sky dark?”

Peter’s mother chortled happily.

“You have just discovered Olber’s Paradox!” she said. “Back in 1823, an astronomer by the name of Olber made famous a problem that had puzzled astronomers since Kepler’s day: ‘if the universe is infinite and there are stars wherever we look, then why is the night sky dark?'”

“So what is the answer?” demanded Peter.

“I’ve given you enough hints to know the answer,” his mother replied.

“You said “if the universe is infinite-‘” Mary started.

“That’s it!” Peter exclaimed. “The universe isn’t infinite!”

“Got it in one!” his mother said. “The solution to the paradox is that the universe isn’t infinite. As a matter of fact, it is only about 13.8 billion years old – remember that infinite implies age as well as width – and so there isn’t enough space for an infinite number of stars nor has there been enough time an infinite number of stars to have formed.”

“Gosh!” Mary said.

“Gosh indeed,” replied Peter’s mother. “And now that we’ve solved the paradox, let’s just look at the stars.”

Turning their binoculars skyward, that’s what they did.